1. Field of Invention
The present invention relates to a water purifier. More particularly, the present invention relates to a water purifier with demountable filtering membrane bags.
2. Description of Related Art
Tap water is piped to homes and is added with chlorine to obtain sterile water. However, pipes may be damaged or worn out after long-term use so that water in the pipes is easily contaminated. Therefore, water purifiers have been developed in various types and are popular in homes to purify the piped water before drinking. A water purifier in accordance with prior art comprises a casing, a base, a filtering core, a cover and a check valve. The casing is attached to the base. The casing has an opening through which the filtering core can be demountably mounted in the casing. The cover is attached to the casing to cover the opening of the casing and has an inlet and an outlet. The check valve is mounted to the cover. The filtering core has a through hole and is generally made of fiber material, such as cotton yarn or non-woven textile. The fiber material for the filtering core is made in the form of corrugated and folded configuration. The through hole of the filtering core communicates with the outlet in the cover, while the inlet of the cover communicates with the interior of the casing.
Consequently, water will enter the interior of the casing when the check valve is opened and flow through the filtering core because of water pressure. The filtered water enters into the through hole of the filtering core and eventually flows out of the water purifier through the outlet in the cover. However, conventional water purifier simply uses sieve pores of the filtering core to remove suspended particles and microorganisms from water. This kind of conventional water purifier is generally used for primitive purification and the quality of filtered water is not good enough for safe drinking.
Another type of water purifier in accordance with the prior art is to use membrane separation technique to purify water. The filtering membrane is made in the form of hollow fiber, which has been developed by a Japanese company, Mitsubishi or an American company, ZENON. The hollow fibers are bound and put into a tube. Water can be purified when passing through the tubes that hold the hollow fibers. However, the hollow fibers will trap the suspended particles and microorganisms in water and eventually become polluted after long-term use. Water cannot be completely purified in such circumstance if the hollow fibers are not replaced. Therefore, this type of water purifier is only suitable for people who live in areas with high quality water.
Furthermore, the membrane separation technique also includes filtering water by using thin membranes for reverse osmosis (RO) or ultra filtration (UF) applications. The filtering core for RO or UF applications is made in the form of a reel by means of bundling and folding the thin membrane by a spiral-wound method. Pressure is applied to water to force water to pass though the thin film composite (TFC) membrane to generate fresh water and the rest water with pollutants is drained.
However, the filtering cores regardless of using fibers, hollow fibers or thin film membranes for the aforementioned water purifiers need to be periodically cleaned after long-term use. Sometimes, the filtering core is difficult to be completely cleaned if the filtering cores trap too many water pollutants. This is because the filtering core is solid with only pores or is difficult to be disassembled from the purifier. Therefore, special purpose chemical material is needed to clean the used filtering core, or the filtering core has to be replaced by a new one. Therefore, it is not economical and environmentally friendly for conventional water purifier.
Besides, in order to reduce unpleasant flavor of chlorinated water and organic by-product such as trihalomethanes, benzene or vinyl chloride, an active carbon filter is generally used and connected to the inlet of the water purifier. The active carbon filter can trap organic chemicals and chlorine. However, the core of the active carbon filter is also not demountable so high cost will be expected. Besides, connecting to the active carbon requires configuring pipes, which renders the entire water purifier bulky and complex.
Therefore, there is a need to provide an improved water purifier to mitigate or obviate the aforementioned problems.